Boron and potassium are required for:

Options

A. Chlorophyll and cytochromes synthesis
B. Translocation of sugars
C. Energy metabolism
D. Stabilisation of ribosomal fractions

Answer

### Step-by-Step Solution:

1. **Understanding the Role of Boron and Potassium**:
- Boron and potassium are essential nutrients for plants, but they have specific functions. It is important to identify what these elements contribute to plant physiology.

2. **Analyzing the Options**:
- The question provides four options regarding the functions of boron and potassium:
1. Chlorophyll and cytochrome synthesis
2. Translocation of sugars
3. Energy metabolism
4. Stabilization of ribosomal fractions

3. **Evaluating Each Option**:
- **Option 1: Chlorophyll and Cytochrome Synthesis**:
- Magnesium is primarily responsible for the synthesis of chlorophyll and cytochrome. Therefore, this option is incorrect for boron and potassium.

- **Option 2: Translocation of Sugars**:
- Boron is known to play a crucial role in the translocation of sugars and carbohydrates in plants. Potassium also aids in this process by regulating osmotic pressure and enzyme activity. Thus, this option is correct.

- **Option 3: Energy Metabolism**:
- Phosphorus is the key element involved in energy metabolism, particularly in the formation of ATP and NADP. Therefore, this option is incorrect for boron and potassium.

- **Option 4: Stabilization of Ribosomal Fractions**:
- Magnesium is essential for the stabilization of ribosomal fractions, specifically for the attachment of the 50S and 30S subunits. Thus, this option is also incorrect for boron and potassium.

4. **Conclusion**:
- After evaluating all options, the correct answer is that boron and potassium are required for the **translocation of sugars**.

### Final Answer:
Boron and potassium are required for the **translocation of sugars**.

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